This invention relates to cross-connect provisioning.
Synchronous data communications networks can carry payload data using, for example, the synchronous digital hierarchy (SDH) protocol or synchronous optical network (SONET) protocol. In each of these protocols, payload data is transported within synchronous payload envelopes (SPE's), in which the payload data is organized into rows. Typically, each row is subdivided into a plurality of data segments, each of which may comprise one or more bytes of data. For example, a virtual connection level 4 (VC-4) may include 63 tributary unit level 1, rate 2 signals (TU-12s) or 2 low order virtual connection level 3 signals (VC-3s) and 21 TU-12s. The VCs are transported across a network in frames known as synchronous transport module (STM) frames. Similarly a synchronous optical network (SONET) system carries data in high order structures known as synchronous transport signals (STS) or low order structures known as virtual tributaries (VTs). An STS-1 may comprise some combination of lower signals such as 28 VT1.5s or 21 VT2s, where VT2s are comparable with SDH TU-12s.
If a VT/TU cross-connect has the ability to cross-connect the overhead column in a SONET/SDH frame as well as the VT/TU data, the cross-connect can operate as an STS-1/VC-3 cross-connect. Cross-connects capable of switching STS-1/VC-3 are typically capable of switching any concatenated rate (e.g. STS-3c/VC-4 to STS-Nc/VC-4-Nc) or other integer multiple rate of 51.84 Mbps.